Air brake



Sept. 12, 1939. r A, CANIP ELL 2,172,498

AIR BRAKE Filed Nov. 50, 1938 3 Sheets-Sheet 1 Jig/.4 27

26% EMGY.SER.. LAP RUN REL 21 L RETURN Q5 2 3 51212, ZMW W- M.

(Ittomegs D 9 9- c, A-. CAMPBELL 2,172,498

AIRBRAKE Filed Nov. -50, 1938 s Sheets-Sheet s EMERGENCY Q GRADUATE!) RELEASE LA? W 8 46 69 M 9 65 4 m... A 45 QVIIIIV Z'+.|'//I/VI |:||l4/A /Am//" 65 Quai 21 '75 4 RELEASE- AUXILIARY RES.

LSMENTALY 2s ssRvomJ Ihwentor Gttomeg:

amaewmaa Patented Sept. 12, 1939 FATENT OFFICE AIR BRAKE Charles A. Campbell, Watertown, N. Y., assignor to The New York Air Brake Company, a corporation of New Jersey Application November 30, 1938, Serial No. 243,281

15 Claims.

This invention relates to electropneumatic brakes, and particularly to a system in which ordinary applications are made electrically, that is, without the participation of any automatic 5 valve and in which there is present an automatic valve serving as a standby and so related to the electric system that if that fails, the automatic valve Will respond to a pneumatic control which is always exercised as an incident to the exerlO cise of the electric control.

This principle of operation diifers quite markedly from that of commercial electropneumatic systems. A typical example of such systems is shown in the patent to Campbell, No. 1,702,152,

15 dated February 12, 1929, which illustrates the P.

S. brake. This has long been standard equipment in local passenger service on a railroad running out of Chicago.

It is characteristic of systems of this type, that 20 the engineers brake valve may be an ordinary equalizing discharge brake valve equipped with an auxiliary switch mechanism to control electric circuits according to the functional positions of the brake valve. Thus, electric manipulation 25 parallels the pneumatic manipulation, so that if the electric control fails, the pneumatic control will take effect. Pneumatic control normally does not take actual effect, but only because the electric control is faster and anticipates it. In

30 such system, the magnet valves-which exercise electric control are associated with an automatic valve (which is basically a triple valve) and do not themselves directly control the brake. They put the automatic valve through its functional 35 movements and cause it to respond more rapidly than, but in the same way that it would respond to the simple pneumatic control. Consequently, although the electric mechanism exercises the control, the triple valve is not merely a standby;

4 it is an active participant in the control and subect to all the wear and consequent depreciation which is attendant .on use.

Experience with these systems has shown that the electric side of the system is now so highly 45 developed and so reliable that failures on the electric side are of extremely rare occurrence, so rare that one might be tempted to consider a simple electric control without any triple Valve. However, such a control would not be accepeted for use a on American railroads and cannot be recommended by reasonably conservative brake engineers. The possible results of a single failure are too serious to be considered.

The purpose of the present invention is to con- 55 vert the automatic Valve or triple valve from a participant in electropneumatic braking, to a standby which is so conditioned by the operation of a simple electropneumatic braking device that the automatic valve does not respond when the electric control is effective, and does respond to 5 pneumatic control immediately upon failure of any element of the electric control.

Generally stated, the system includes an engineers brake valve exercising ordinary pneumatic control through a brake pipe. This valve has electric contacts which close circuits according to the various pneumatic positions, but the electric control instead of anticipating the pneumatic response of the triple valve, forestalls it. The triple valve remains at rest in release position despite the pneumatic control which tends to render it active, so long as the electric mechanism is effective. If any part of the electric mechanism fails, the pneumatic system responds to pneumatic control and performs the ordinary functions of an automatic air brake. In this Way, the pneumatic system and particularly the triple valves are relieved of wear, and if given reasonable periodic inspections will perform, when called upon, as certainly and effectively as they would perform had they spent the intermediate period in active participation in brake control.

Thus stated, the scheme sounds very simple, but there are a number of considerations that complicate the problem. The solution of these difiiculties is an important element of the present invention.

In order that the importance of certain features may be appreciated as the description proceeds, a brief recapitulation of the operating characteristics of the system will be given.

The triple valve has a charging port open in release position and so arranged as to permit rapid charging flow from the brake pipe to the slide valve chamber of the triple valve, but only slow back flow. When the engineers brakevalve, which is of the equalizing discharge type, is placed in service position it causes energization of a service magnet valve and this operates through a pneumatic relay to admit air from the slide valve chamber of the triple valve and from the connected auxiliary reservoir to the brake cylinder.

The rate of flow is predetermined and is so chosen, that the charging port draws on the brake pipe for air and reduces brake pipe pressure at a rate slightly faster than the rate at which the engineers brake valve, in service position, reduces equalizing reservoir pressure. Hence the equalizing discharge valve of the engineers brake valve does not open and the triple valve is held in release position.

Thus if the electric system functions in service the pneumatic mechanism is inert.

It is now the usual practice to use a supplemental reservoir to augment brake cylinder pressure in emergency applications. Since this reservoir can best be charged through the triple valve in release position, in which position the brake cylinder exhaust is opened through the triple valve, and since the valve remains in release position during electric applications, there must be some means to interrupt communication between the supplemental reservoir and the triple valve and between the triple valve exhaust port and atmosphere, as an incident to an application produced by the service magnet valve. Other- Wise, the charge in the supplemental reservoir could not be held in reserve and braking pressure could not be retained in the brake cylinder. It is simple to control these communications electrically, but such controls cannot be independent of the application control, because the failure of one control while another is active may result in complete failure of the system. Thus, a feature of the invention is the provision of an electro-pneumatic interlock between the service magnet, whose energization controls the supply of air to the brake cylinder, and the intercepting means for the supplemental reservoir and for exhaust.

A characteristic of the preferred interlock is that the release magnet valve which closes exhaust'is energized in lap position (as well as in service position) and in lap position establishes a connection, maintained in service position, through which the service magnet must be energized in service position. Consequently, the exhaust port must be closed before air can be admitted to the brake cylinder by the service magnet valve.

Another characteristic of the interlock is that if, at any time, the release magnet circuit which controls closure of the triple valve exhaust port should fail, all the electric circuits would be interrupted and the triple valve would thereupon operate pneumatically.

To ensure immediate and certain pneumatic response of the triple valve, the exhaust porting of the triple valve is so arranged as to afford, in

conjunction with the interlock and the control over the exhaust intercepting and supplemental reservoir intercepting valves, certain accelerating features which become effective if the release circuit should fail during the making or retention of an electric application.

The exhaust ports extend through the main slide valve and are so controlled by the graduating valve as to be closed if the triple piston shifts from release toward service position an amount somewhat less than the lost motion be tween the piston and slide valve.

If release and application circuits are both valves open and the application circuit is interrupted. Back flow from the supplemental reservoir to the triple slide valve chamber hastens the shift of the triple piston to close the charging and exhaust ports and then to establish pneumatic service flow. If the engineers brake valve is left in service position the equalizing discharge valve will open in response to falling equalizing reservoir pressure.

If an electric application has been made and the engineers brake valve is in lap position, only the release circuit .is energized. The equalizing discharge valve remains closed. If the release circuit then fails the pressures on the opposite sides of the triple piston are substantially equal. However, failure of the release circuit opens the supplemental reservoir intercepting valve, and back flow to the triple slide valve chamber from the supplemental reservoir raises slide valve chamber pressure and thus shifts the piston and graduating valve. This shift closes the exhaust port before the supplemental reservoir port is closed. a

The porting just described is so arranged that during simple pneumatic operation it offers graduated release.

A preferred commercial embodiment of the invention will now be described with reference to the accompanying drawings, in Which- Figure 1 shows in elevation the main reservoir, feed valve, and engineers brake valve, together with the switch operated by the engineers brake valve and the application wire, release wire, and the common or return wire.

Fig. 2 shows in diagrammatic section the magnet valve portion of the brake valve which includes the magnet valves, the relay valves Which they control, and the electropneumatic interlock.

Fig. 3 shows in diagrammatic section the pipe bracket with connections to the auxiliary reservoir, supplemental reservoir and brake cylinder, and also shows the triple Valve mounted on the pipe bracket. The triple valve is shown in release position. 7

Note: It will be understood that the magnet valve portion of Fig. 2 is intended to be mounted directly on the left face of the pipe bracket shown in Fig. 3. Figs. 1, 2 and 3, when assembled in the order stated, from left to right, with the magnet valve mounted as stated, comprise a diagram of the control unit and one braking unit.

Fig. 4 is a diagrammatic development of the electric control switch associated with the engineers brake valve. On this view, the positions of the contactor in release, running, lap, service and emergency positions of the engineers'brake valve are indicated by legends.

Fig. 5 is a section through the charging port of the triple valve designed to indicate how it is arranged for large flow capacity.

Fig. 6 is a fragmentary diagram of the slide valvewith its seat and graduating valve, the

parts being shown in service position.

Fig. 7 is a similar View showing service lap position.

Fig. 8 is a similar View showing emergency position; and

Fig. 9 is a similar view showing graduated release lap position. 7

Figs. 2, 3 and 6 to 9, inclusive described as diagrammatic, are so to the extent that all ports are drawn as if in the plane of section. In practice other more compact arrangements are possible and can be evolved by the use of mechanical skill.

Referring first to Fig. 1, the main reservoir is shown at l I and the. brake valve at l2. The brake Valve is of the ordinary equalizing discharge type equipped with an equalizing reservoir l3 and fed from the main reservoir both directly through pipe I4, and indirectly through the pressure reducing feed valve I5.

The valve will be described as a five position valve, the positions being release, running, lap, service and emergency. If a large capacity feed valve (such as type F of the New York Air Brake Company) be used, release position is not needed. Engineers valves having more positions could be used, but since the added positions would have no functional significance with respect to the present invention, it is unnecessary to discuss these beyond negativing any intent to exclude the use of such valves.

The brake pipe is given the numeral I6 whereever it appears. There is an ordinary cut-out cock at II, but this cock is normally open. The train pipe l6 runs throughout the length of the train and will be connected from car-to-car and to triple valves on the various cars in the usual manner. Also extending throughout the length of the train and connected from car-to-car in any convenient manner are three electric conductors herein designated as the release wire 18, the service wire l9, and the common return wire 2|. A distinct return conductor is considered better than a grounded return, but is typical of any common return necessary to complete the application magnet circuit and the release magnet circuit.

Mounted on top of the housing of the engineers brake valve I2 is a shell 22 containing three arcuate fixed contacts which are engaged in the relationship hereafter set forth by a contactor swinging with the brake valve handle 23 and indicated at 24 in Fig. 4. As stated, Fig. 4 is a development of the arcuate contacts. In the shell 22 is a return contact 25 with which the contactor 24 engages in all positions of the engineers brake valve. This is connected to the return wire 2! and in this the current source or battery 26 is interposed. A cut-out switch 2'! is provided to cut out the electric control when desired. Also, in the shell 22 are two contacts, 28 and 29. The contact 28 is a release contact connected with the release wire l8 and engaged by the contactor 24 only in lap and service positions of the engineers brake valve. Contact 28 is a service contact connected with the service wire I9 and engaged by the contactor 24 only in service application position.

To recapitulate the positions of the engineers brake valve: In release position main reservoir air is fed to the brake pipe without pressure reduction and wires [8 and [9 are deenergized. In running position main reservoir air is fed to the brake pipe through the feed valve 15 at reduced pressure, that is, at normal brake pipe pressure, and wires l3 and [9 are deenergized. In lap position, all communications to and from the brake pipe are closed, wire I8 is energized and wire I9 is deenergized. In service position, supply of air to the brake pipe is cut off, the equalizing reservoir i3 is vented at a restricted rate and both the wires l8 and is are energized. In emergency position the supply of air to the brake pipe is cut off, the brake pipe is vented freely to atmosphere, and both Wires [8 and I9 are deenergized. This provides for the entire control of the system, both electric and pneumatic.

Turning now to Fig. 3, the reference numeral 3! represents an ordinary pipe bracket intended to be attached to the body of a car and having ports formed in the body leading through branch pipes to an auxiliary reservoir 32, .a supplemental reservoir 33, a brake cylinder 34 and the brake pipe l6. To simplify the lettering, the branch pipes are given the same reference numerals as the ports in the body, as they are simply continuations of these ports. Thus, the auxiliary reservoir port is indicated at 35, the supplemental reservoir port at 36, the brake cylinder port at 3'! and the brake pipe port at 38. There is also formed in the pipe bracket an intermediate exhaust port 39 which, as will be explained later, leads from the triple valve exhaust port to the exhaust intercepting valve and also a terminal exhaust port 4| which leads from said intercepting valve to atmosphere. All branches in all ports in the pipe bracket 3| are given the characteristic port number.

Mounted against the left face of the bracket 3! is a magnet valve body 42, and mounted against the right face of the bracket 3! is the body Q3 of the triple valve.

The triple valve body 53 has the usual bushed slide valve chamber 45 with ported seat for the main slide valve 35. On the top of the slide valve 55 is a graduating valve 46. These valves are operated by the stem d? of the triple piston as. The piston 58 has the usual packing ring and Works in the usual cylinder bushing in response to pressure diiferentials between the slide valve chamber 44 and the brake pipe chamber 4% which is in free communication with the brake pipe port 38. The stem 4? shifts the graduating valve 4% positively, the valve being closely confined in a notch in the stem i? and urged to its seat by a small leaf spring as shown. This arrangement is conventional and is adequately illustrated in the drawings.

The main slide valve 35 is held to its seat by the usual bow spring, clearly shown in the drawings. It has limited lost motion with reference to the stem M. The lost motion is such that as the piston 48 starts outward, that is to the left, the graduating valve is may shift on the main slide valve 45 far enough to open the service port, close the exhaust port, and close the supplemental reservoir charging port before the main slide valve 15 is moved at all. Thus, the graduating valve is moved first and the limit of such motion is indicated in Fig. 9 as graduated release lap position.

Continued outward motion moves also the slide valve 45. Service position, which is indicated in Fig. 6, is reached when the hub of the piston 53 engages the thimble-shaped graduating stop 5i yieldingly positioned by the graduating spring 52.

If the piston 48 moves to the right from service position, it first shifts the graduating valve to the right by the amount of the lost motion relatively to the main slide valve 65. The main slide valve remains at rest. The parts thus assume service lap position (Fig. '7) in which the service port is closed by the graduating valve.

In response to emergency reduction in brake pipe pressure, the piston 48 moves outward to the limit of its motion, seating on the gasket which the joint between the pipe bracket 35 and triple valve body as. To do so it must overpower the spring 52. The slide and graduating valve are then in emergency position (Fig. 8).

The seat for the slide valve 45 has a number of ports. There is a supplemental reservoir port 55 which leads through the body iii of triple valve, the pipe bracket 3! and the body d2 of the magnet valve unit to a supplemental reservoir intercepting valve hereinafter described. intercepting valve controls communication with the supplemental reservoir port 3%. Next, there is an exhaust port .55 which leads to the intermediate exhaust port 39 in the bracket 3!. Next, there are two brake cylinder ports 56 and 57, both of which are in free communication with the brake cylinder port 31. Next, there is a third brake cylinder port 58 which is in restricted communication with the brake cylinder port 3'! by way of a flow restricting choke 59. Finally, there is a safety valve port 6| which leads to a safety blowdown valve 62 whose function is to limit brake cylinder pressure.

Referring now to the slide valve 45, there is a through port 63 which is controlled at its upper end by the graduating valve and opened thereby alternatively and selectively with reference to the through port 64 which is the service port. The port 63 registers with the port 54 when the triple valve is in release position (Fig. 3) and graduated release lap position (Fig. 9) and is blanked at the seat at other times. The service port 64 registers with the port 58 in service, service lap and emergency positions. It is blanked at the seat in other positions. There is a supplemental reservoir return flow port 65 which registers with the port 54 in emergency position. It is not controlled by the graduating valve and is the means by which supplemental reservoir air may flow back to the slide valve chamber and thence to the brake cylinder in emergency applications. There are two through ports 66 and 61 which in the release position of the slide valve 45 and only in such position, register with the brake cylinder port 56 and with the exhaust port 55. When the graduating valve 46 is in its inner or right hand position, a cavity 68 in the lower face of the graduating valve connects the ports 66 and 61 and thus provides for exhaust flow. This exhaust path is thus open only in full release position (Fig. 3). It will be observed that the exhaust flow path may be interrupted either at the seat or at the graduating valve, or both. See Figs. 6, '7, 8 and 9.

Motion from release position (Fig. 3) to graduated release lap position (Fig. 9) is relied upon to cut off release flow if the release circuit should fail, causing opening of the supplemental reservoir cut off valve while the engineers brake valve is in lap position. Under such circumstances back flow of supplemental reservoir air through port 63 shifts piston 48'outwardly and closes the exhaust port path at the graduating valve seat slightly before the port 63 is closed.

There is a cavity 69 in the main slide valve 45 which connects the brake cylinder port 57 to the safety valve port 6| in release, service, servicelap, and graduated release lap positions, but not in emergency position. Hence, the safety valve is effective in all service applications, whether produced electrically or pneumatically.

The charging arrangement is quite different from that ordinarily used. When the piston 48 is in its release position (Fig. 3), it exposes a series of charging ports 1| through which rapid flow can occur. Charging air passes the ball check valve 12 and the rubber check valve 13, which last is seated by a light spring 14 to auxiliary reservoir port 35. This permits direct and rapid charging flow from the brake pipe 96 by way of port 38, chamber 49, charging ports H, and the check valves 12 and 13 to the slide valve chamber 44 and to the auxiliary reservoir 32. Since the triple valve is in release position (Fig. 3), there will also be charging flow to port 54 and thence to the supplemental reservoir 33 assuming the intercepting valve hereinafter described be open, as it'necessarily is under releasing and charging conditions. Back flow from the auxiliary reservoir and slide Valve chamber to the brake pipe is limited to the capacity of the relatively small choke 75. The purpose of this is to permit rapid flow from'the brake pipe toward the auxiliary reservoir but only very slow reverse flow. Mounted in the magnet valve housing 42 is service relay diaphragm valve which is normally closed and which controls communication from the auxiliary reservoir passage 35 to the brake cylinder port 31, a choke 16 being interposed in the latter port to limit the rate of flow when the relay valve is opened. The relay valve proper is a rubber seated valve TI connected to the center of the diaphragm 18 which is clamped at its periphery between a portion. of the valve body 42 and a removable cap 79. The valve is urged in a closing direction by a coiled compression spring 8| and, hence, closes when the pressures on the opposite sides of the diaphragm approach equalization. The lower face of the diaphragm outside the seat for the valve 11 is subject to auxiliary reservoir pressure. The space above the diaphragm 18 may be subjected to brake pipe pressure or to atmospheric pressure. The valve is closed when its actuating diaphragm is subjected to brake pipe pressure and opens when the space behind the diaphragm is vented to atmosphere.

Control is effected by a double beat admission and exhaust poppet valve 82 biased by a spring 83 to close atmospheric exhaust port 84 and open an admission port 85 to which air is communicated by a branch of the brake pipe passage 38. The controlling winding, called the service magnet winding, is indicated at 86. When this winding is deenergized, the valve 11 is closed. When the winding is energized, the space above diaphragm l8 is vented, the valve 11 opens and flow occurs from the auxiliary reservoir to the brake cylinder at a rate determined by the flow capacity of the choke l6. 5

The capacity of the choke 16 is so chosen that flow to the brake cylinder will lower the pressure on the right hand side of the triple piston 48 at a rate sufficiently high to cause the triple valve to remain in release position and draw on the brake pipe for air by flow through the charging ports ll. Further the rate of flow is such that each triple valve will reduce pressure in the corresponding portion of the brake pipe, at a rate a ing direction by the spring 89 and which controls flow through the intermediate exhaust port 39 to the atmospheric exhaust port M. The rate of flow is controlled by a choke 3! which may be inserted at any convenient point and is shown mounted in the left face of the pipe bracket 3!. The valve 88 is normally held open or unseated by a piston 92 which, except during electric applications, is held in its uppermost position and when so held engages the stem 93 of the valve 38 and holds it from its seat. In its normal or upward position, the piston 92 produces a seal with the rib 94 on the bushing in which it WOl'kS. 75

by means or the rubber facing carried by the piston. The intercepting valve which isolates the supplemental reservoir during electric application, is a rubber poppet valve 96 which is urged toward its seat by a spring 91. This valve controls communication between the supplemental reservoir port 36 and the port 54 which leads to the seat of the triple slide valve.

Except during electric applications, valve 96 is held from its seat by a mushroom-shaped thrust member 98 which is forced downward by a flexible diaphragm 99. This diaphragm is clamped at its periphery between a portion of the body 42 and a cap IOI. This cap also houses a thrust spring I02 which reacts downward on the diaphragm 99 through a cup-shaped thrust plate I03. The chamber I04 beneath the piston 92, and the space within cap IOI above diaphragm 99 are normally subject to supplemental reservoir pressure.

A double beat poppet valve I05 is biased by a coil compression spring I06 toward the atmospheric exhaust seat I01, and when the exhaust port is closed the valve opens the supply port I08 leading from the supplemental reservoir port 36. The valve may be shifted from the stated position by excitation of the release magnet winding I09, and when so shifted, closes the supply port I08 and opens the exhaust, through seat I0'I, so that chamber I04 is vented and the space above the diaphragm 99 is likewise vented. The effect is to cause closure of the exhaust intercepting valve 88 and the supplemental reservoir intercepting valve 96.

The Winding I08 is connected between the release wire I8 and the common return wire 2|, so that the release magnet winding is always energized in lap position and in service position. Consequently, it is not only energized during a service application, but is energized as the brake valve moves from running, through lap, toward service position, and after the engineers brake valve is returned to lap position. Thus, the two intercepting valves function before the application valve can operate to admit air to the brake cylinder, and continue to function when the engineers brake valve is shifted back to lap position.

Since energization of the release valve must occur before it is safe to energize the application magnet winding 86, an interlock is used which conditions the application circuit to operate as a result of the energization of the release magnet winding I99. This interlock responds to pressure conditions in the chamber I04 and is housed in a casing I II mounted on the lower end of the body 42.

Clamped between the casing III and a ported cap H2 is a diaphragm II3 subject on its upper face to pressure in chamber I04. The cap IIZ carries a stop lug I I4 which limits the downward movement of the piston 92. The diaphragm II3 operates through a mushroom-shaped push rod II5 which is urged upward by a coil compression spring II6 upon a resilient contactor I I7. When the diaphragm is held downward, as it is whenever the winding I09 is deenergized from any cause, the contactor II! is held away from the contact H8. The contactor II! is connected to the service wire I9. The contact H8 is connected to one terminal of the application winding 86. The other terminal of this magnet winding is connected to the common return wire 2|. Thus, energization of the release magnet winding I09 not only causes closure of the two intercepting valves, but it establishes an electric connection from the application wire to one terminal of the application magnet 86.

Remembering that the release magnet is energized in lap and in service positions, it follows that if the circuit is intact, and only if it is intact, the application magnet winding 86 can be energized in service position. Thus, the system has only two circuits, and only two magnet valves per braking unit. The magnet valves are normally deenergized. In electric service applications, the release magnet valve must function in a way which will cause closure of the exhaust port and isolation of the supplemental reservoir before the application magnet can function to deliver air from the auxiliary reservoir to the brake cylinder.

Operation Pneumatic operation.If the switch 21 is open, the braking system will operate as a simple pneumatic system.

The charging flows will be obvious and the service function and service-lap function follow well recognized automatic air brake principles. The upper side, of the diaphragm I0 is subject to brake pipe pressure but the spring 8| holds valve 11 closed during service reduction of brake pipe pressure.

Graduated release may be had by pneumatic operation and this also is in accordance with past practice. In fact, the triple valve very closely resembles the L triple valve in all features except emergency.

In emergency position, the triple valve moves to its full outward position in which both the auxiliary and the supplemental reservoirs supply air to the brake cylinder. Valve II will open in response to emergency reduction of brake pipe pressure.

Electric operation-The switch 21 would normally be closed. In running and release position of the engineers brake'valve, the functions are simply those characteristic of a pneumatic system. When the brake valve handle is moved into lap position, the release circuit is energized so that the winding I09 is energized, chamber I04 is vented to atmosphere, and, consequently, the exhaust intercepting valve 88 closes and the supplemental reservoir intercepting valve 96 closes. The venting of chamber I04 also allows the diaphragm II3 to rise, so that the contactor I I! conditions the application circuit on that particular car to function. When the engineers brake valve is moved into service position, the service wire I9 is energized, the winding 86 is energized, the space above the diaphragm I8 is vented, and the valve TI opens to admit auxiliary reservoir air to the brake cylinder at a rate controlled by the choke 16.

As explained, the triple valve stays in release position but exhaust does not occur because valve 88 has closed. The supplemental reservoir 33 is held in reserve because the valve 96 is closed. The equalizing discharge valve of the engineers brake valve remains closed.

After sufficient application has been made, the engineer moves his brake valve to lap position in which winding 86 is deenergized and winding I09 remains energized. Consequently, the valve 'I'I closes and the valves 88 and 96 remain closed.

Release-The engineer can make a complete release of the brakes on moving the brake handle to either running or release position, and can produce a graduated release by moving the brake valve momentarily to running position and then back to lap position, in the familiar manner. The manipulation is practically the same that it would be with a pneumatic graduated release.

Emergency application-Emergency application is purely pneumatic and the. electric mechanism does not participate therein. If an emergency application follows an electric service application, the sudden complete venting of the brakepipe will cause the triple valve to move to emergency position and connect both reservoirs with the brake cylinder.

Safety features.The critical point in the system is the maintenance of exhaust valve 88 closed and in all circumstances under which the brake application could be lost through the triple valve exhaust. The closure of the exhaust valve (and the closure of the reservoir intercepting valve) is dependent on energization of the release winding I09. If this fails, the triple valve must assume an application position or brake failure will result. There are three conditions: The failure might occur under running condition, that is, before any application is attempted; it might occur while an electric application was being made; or it might occur while an electric application is being held in lap position through the engineers brake valve.

Under the first of these three conditions, winding I09 could not be energized. Consequently, winding 86 could not be energized and the triple valve would. simply function pneumatically. Un-

release magnet establishes conditions which safeder the second condition, prior to the interruption of the release magnet circuit, both windings 85 and H19 would be energized. Deenergization of winding I 09 entails deenergization of winding 86. Consequently, valve 11 closes and valves 88 and 96 open. The opening of the valve 96 feeds air back through the port 54 to the slide valve chamber of the triple valve, and starts the latter toward service position, closing the charging port and brake cylinder exhaust port.

Remembering that we have assumed that an application is being made, that is, that the equalizing reservoir is beingvent'ed, the arrest of brake pipe pressure reduction at the triple valves causes the equalizing discharge valve to open and cause brake pipe pressure reduction with consequent service movement of the triple valves.

7 The third assumption is that the engineers brake valve is in lap position so that the equalizing discharge valve is closed. Under these condi tions, winding 86 is already deenergized. Deenergization of winding I09 causes valves 88 and 96 to open, choke 9| delays exhaust flow, and the back feed of air from the supplemental reservoir to the slide valve chamber shifts'the triple valve to graduated release lap position (Fig. 9) in which the charging port'is closed and the exhaust passage is closed at the triple valve. Consequently, failure of the release circuit or the car should fail while the circuits for the trainv remained operative, the triple valvefor that par ticular car would function pneumatically despite the fact that equipment on other cars was functioning electrically. Proper proportioning of charging ports will ensure reasonably harmonious action under such conditions.

Any known type of electric emergency propagation could be imposed on the system-i. e., could be aggregated therewith, but this is not considered necessary or patentable and hence is not illustrated. The claimed system does not exclude the use of electrically propagated emergency applications by means heretofore used in the electric pneumatic brake art.

While one embodiment of the invention has been described in considerable detail, and is preferred for practical reasons, it is fully recognized that modifications are possible within the scope of the invention and, therefore, the description is to be taken as illustrative and not limiting, the scope of the invention being defined solely by the claims.

What is claimed is:

1. The combination with an automatic brake system including a brake pipe, an engineers brake valve, and at least one braking unit comprising a triple valve connected to be controlled by the pressure changes in the brake pipe, and an auxiliary reservoir and brake cylinder connected with the triple valve, said triple valve having a release position in which it opens an exhaust from the brake cylinder and charges the reservoir from the brake pipe, and a service position in which it closes such exhaust and supplies auxiliary reservoir air to the brake cylinder at a restricted rate,-

of an electric accelerating means arranged to be energized during the making of service applications, and comprising electric means serving when energized to supply air from the auxiliary reservoir directly to the brake cylinder at a rate sufliciently faster than that characteristic of service position of the triple valve to prevent service movement of the triple valve; electric means arranged to be energized during service applications and serving when energized to intercept exhaust flow from the brake cylinder independently of the triple valve; and means for preventing energization of the first electric means unless the second be energized. g

2. The combination defined in claim 1 in which each of the electric means comprises a pressure motor actuated valve and an electrically actuated pilot valve controlling the operation of the motor 7 position in which said exhaust is closed and aux-- iliary reservoir air is fed to brake cylinder, said triple valve moving to service position in re sponse to a slow or service rate reduction of brake pipe pressure; of electric means arranged to be energized during service applications and serving when energized to supply auxiliary reservoir air directly to brake cylinder at a rate which will reduce auxiliary reservoir pressure faster than the service rate of reduction of brake pipe pressure; electric means arranged to be energized during service applications and serving when energized to intercept exhaust fiow from the brake cylinder; and means to inhibit energization of the first electric means except when the second is energized.

4. A secondary electric control unit for use with a triple valve of the graduated release type adapted for connection with auxiliary reservoir, supplemental reservoir, brake cylinder and brake pipe, said control unit comprising in combination; electric means serving when energized to establish a direct flow connection from auxiliary reservoir to brake cylinder; electric means serving when energized to intercept exhaust flow from the brake cylinder and intercept flow between supplemental reservoir and triple valve; and means for preventing energization of the first named electric means except when the second is actually energized,

5. A secondary electric control unit for use with a triple valve of the graduated release type adapted for connection with auxiliary reesrvoir, supplemental reservoir, brake cylinder and brake pipe, said control unit comprising in combination; a pressure motor operated inlet valve controlling flow from auxiliary reservoir to brake cylinder; a shiftable inlet and exhaust pilot valve controlling said motor operated valve; means biasing the pilot valve to a position for closing said inlet valve; electric means serving when energized to shift said pilot valve against said bias; intercepting valve means for intercepting exhaust through the triple valve and for intercepting communication between the supplemental reser voir and triple valve; motor means for operating said intercepting valve means; a second inlet and exhaust pilot valve for controlling the last named motor means; means for biasing the second pilot valve to a position for causing the motor means to maintain the intercepting valve means open; a second electric means serving when energized to shift said second pilot valve against said bias; and means for preventing the energization of the first named electric means except when the second electric means isenergized.

6. A secondary electric control unit for use with a triple valve of the graduated release type adapted for connection with auxiliary reservoir, supplemental reservoir, brake cylinder and brake pipe, said control unit comprising in combination; a pressure motor operated inlet valve controlling flow from auxiliary reservoir to brake cylinder; a shiitable inlet and exhaust pilot valve controlling said motor operated valve; means biasing the pilot valve to a position for closing said inlet valve; electric means serving when energized to shift said pilot valve against said bias; intercepting valve means for intercepting exhaust through the triple valve and for intercepting communication between the supplemental reservoir and triple valve; motor means for operating said intercepting valve means; a second inlet and exhaust pilot valve for controlling the last named motor means; means for biasing the second pilot valve to a position for causing the motor means to maintain the intercepting valve means open; a second electric means serving when energized to shift said second pilot valve against said bias; and pressure operated switch means for preventing the energization of the first named electric means except when the second pilot valve has been shifted against its bias.

'7. A secondary electric control unit for use with a triple valve of the graduated release type adapted for connection with auxiliary reservoir,

supplemental reservoir, brake cylinder and brake pipe, said control unit comprising in combination; a pressure motor operated inlet valve con trolling flow from auxiliary reservoir to brake cylinder; a shiftable inlet and exhaust pilot valve controlling said motor operated valve; means biasing the pilot valve to a position for closing said inlet valve; electric means serving when energized to shift said pilot valve against said bias; intercepting valve means for intercepting exhaust through the triple valve and for intercepting communication between the supplemental reservoir and triple valve; means biasing said intercepting valve means to close; motor means for operating said intercepting valve means; a second inlet and exhaust pilot valve for controlling the last named motor means; means for biasing the second pilot valve to a position for causing the motor means to maintain the intercepting valve means open; a second electric means serving when energized to shift said sec ond pilot valve against said bias; and means for preventing the energization of the first named electric means except when the intercepting valve means have been allowed to close.

8. The combination of an automatic air brake system comprising, an engineers brake valve having an application position, a lap position and at least one brake releasing position, a brake pipe, an auxiliary reservoir, a brake cylinder, and a brake controlling valve device responsive to pressure differentials between brake pipe and auxiliary reservoir, and having a release position in which it charges the reservoir from the brake pipe and exhausts the brake cylinder; electromagnetic means serving when energized to cause admission of auxiliary reservoir air directly to the brake cylinder; electromagnetic means serving when energized to intercept exhaust from said brake cylinder; means for preventing energization of the first electromagnetic means except when the second is energized; and means operated concurrently with said engineers brake valve and serving to deenergize both said electromagnetic means in said releasing position, energize both in said application position and energize the second alone in lap position.

9. The combination defined in claim 8 in which the engineers brake valve is of the equalizing discharge type and the first named electromagnetic means is so proportioned as to reduce aumliary reservoir pressure, and consequently brake pipe pressure by fiow through the charging path, at a rate which will inhibit response of the equalizing discharge mechanism of the engineers brake valve.

10. The combination of an automatic air brake system comprising an engineers brake valve having an application position, a lap position and at least one brake releasing position, a brake pipe, an auxiliary reservoir, a supplemental reservoir, a brake cylinder and a triple valve of the graduated release type having a triple piston responsive to pressure differentials between brake pipe and auxiliary reservoir, a main slide valve and a graduating valve both shiftable by said piston and the graduating valve being shiftable relatively to the main slide valve when the latter is in release and charging position, to close exhaust from the brake cylinder and then isolate the supplemental reservoir from the triple valve; electromagnetic means serving when energized to cause admission of air from the auxiliary reservoir directly to the brake cylinder; electromag-- netic means serving when energized to intercept self in .L

1 first electromagnetic means except when the second is energized; and means operated concurrently with said engineers brake valve to deenergize both said electromagnetic means in said releasing position, energize both in said application positions and energize the second alone in lap position.

11. The combination of an automatic air brake system of the graduated release type including an engineers brake valve of the equalizing discharge valve type having a releasing position, a lap position and a service application position in which last it vents an equalizing chamber at a restricted rate to operate the equalizing discharge valve mechanism, a brake pipe connected with said valve, the valve serving to establish pressure in the brake pipe to release the brakes and charge reservoirs, and reduce pressure therein by the operation of the equalizing discharge to apply the brakes in service application, and

, at least one triple valve connected with the brake pipe to be actuated by pressure changes therein, each such triple valve being equipped with auxiliary reservoir, supplemental reservoir and brake cylinder and having a charging port for charging such reservoirs in its release position; electric means one for each triple valve connected to be energized in said service application position of the engineers brake valve and when energized serving to reduce auxiliary reservoir pressure by fiow to the brake cylinder and consequently reduce brake pipe pressure by. flow through the charging port at a rate fast enough to inhibit opening of the equalizing discharge valve mechanism of the engineers brake valve; electric means one for each triple valve connected to be energized whenv said engineers brake valve is in said application and lap positions, and when energized serving to intercept exhaust flow through its triple valve and flow between the supplemental reservoir and its triple valve; and means serving to prevent energization of the first named electrical means except when the corresponding second named electrical means is actually energized.

12. The combination of a brake pipe; an aux iliary reservoir; a supplemental reservoir; abrake cylinder; a triple valve connected with the parts above enumerated and comprising; a triple piston separating brake pipe from a slide valve chamber directly connected with auxiliary reservoir, the piston opening a charging path around position, a slide valve and a coacting graduating valve in said chamber and connected to he differentially actuated by said piston, said valves in release position opening a release pathfrom bralre cylinder and a com-- munication between slide valve chamber snipleinental reservoir, the graduating valve serving to close said release path and communication as thetriple piston starts from. release oward application position; electric means serving when energized to open a flow path from auxiliary reservoir to brake cylinder; electric means serving when energized to close said exhaust path and communication; means inhibiting the energization oi the first named electric means except when the second is energized; and acombined brake valve and switch having at least three functional positions", namely, a brake releasing position in which the brake pipe is charged and 'and' tion position adapted to cause brake pipe pres sure to be reduced at a service rate and in which both electric means are energized; and a lap position in which the second electric means alone is energized.

13. In an automatic air brake system; a normally charged brake pipe; a brake valve manipulable to cause charging of said pipe to establish release and running conditions, and manipulable to condition said brake valve to reduce pressure in said pipe at a service rate to establish service application conditions; at least on'e braking unit comprising a brake controlling valve device oi the automatic type connected with said brake pipe, also a brake cylinder, an auxiliary reservoir and a supplemental reservoir connected with said controlling valve device, the latter having a release position in which it opens an exhaust from brake cylinderancl establishes a charging path from brake pipe to both reservoirs, and a service position in which it closes brakes cylinder exhaust, isolates the supplemental reservoir and admits auxiliary reservoir air at a restricted rate to brake cylinder; electrically controlled means rendered active as an incident to service manipulation of said brake valve to reduce auxiliary reservoir pressure by flow to the brake cylinder at a rate faster than the service rate of reduction of brake pipe pressure which the brake valve is conditioned by service manipulation to produce whereby the brake controlling valve device is caused to stall in release position and brake pipe pressure is reduced by flow through the charging path; and electrically controlled means rendered active as an incident to service manipulation of said brake valve, and when active serving to isolate the supplemental reservoir and intercept exhaust from the brake cylinder independently of the triple valve,

14. The combination with the structure defined in claim 13 of a differential flow device controlling said charging flow from brake pipe to the auxiliary reservoir and so arranged as to permit rapid fiow in a charging direction and restrict back flow.

15. In an automatic air brake syste m; a norinallycharged brake pipe; a brake valve manipulable to cause charging of said pipe to establish release and running conditions, and manipulable to condition said brake valve to reduce pressure in said pipe at a service rate to establish service conditions; at least one braking unit comprising a brake controlling valve device of the automatic type connected with said brake pipe, also a brake cylinder, an auxiliary reservoir and a supplemental reservoir connected with said controlling valve device, the latter having a release position in which it opens an exhaust from brake cylinder and establishes a charging path from brake pipe to both reservoirs, and a service position in which it closes brake cylinder exhaust, isolates the supplemental reservoir and admits auxiliary reservoir air at a restricted rate to brake cylinder; electrically controlled means rendered active as an incident to service manipulation of said brake valve to reduce auxiliary reservoir pressure by flow to the brake cylinder at a rate faster than the service rate of reduction of brake pipe pressure which the brake valve is conditioned by service manipulation to produce whereby the brake controlling valve device is caused to stall in release position and brake pipe pressure is reduced by fiow through the charging path; electrically controlled means rendered active as an incident to service manipulation of said brake valve, and when active serving to isolate the supplemental reservoir and intercept exhaust from the brake cylinder independently of the triple valve; and means for inhibiting the action of the first electrically controlled means unless the second is then active, the parts being so arranged that failure of the second electrically controlled means while service conditions exist and the resulting reconnection of the'supplemental reservoir will cause the brake controlling valve device to shift from release toward service position, closing brake cylinder exhaust and assuming brakingcontrol in response to brake pipe pressure. CHARLES A. CAMPBELL. 

